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Magical! Driving a sub through the “herms” of Pavilion Lake is absolutely magical! Imagine this: a snow of particulates streaks around the dome. A yellow light permeates the water column as it filters through the planktonic cloud and bounces through the Chara. Microbialites rise up from the bottom like castles shrouded in a mist of microalgae. The natural world is like poetry to an observational scientist, and a dive in the herms is high art. Of course, to someone who studies the shapes and forms of microbialites (like I do), a dive in the herms is also like candy! Microbialites cover up to 90 percent of the lake bottom, and exhibit a variety of different shapes in a space of only a few meters. For a microbialite scientist – Yum!

View from the pilot's seat.

Today I was lucky enough to pilot such a dive to the herms. The herms are an area near the center of Pavilion Lake. Their name is a bit of a misnomer – in fact, it is more of a nickname that stuck! Herms is short for bioherms, which refers to a build up of biological organisms, usually into a mound that rises above the surrounding sea or lake floor. Our Pavilion herms are mounds, but they are probably just sediment mounds that are covered in lots of microbialites, rather than being mounds build up exclusively by microbialites. Nevertheless, they remain a favorite area of the PLRP scientific team, because of the small area, dense ecology, and interesting geochemical and limnological environment.

My mission was to completely circumnavigate two of the herms that we had not mapped in previous years. Navigating the subs through an area of such dense mounds and interesting features has been challenging in the past. The topography can make communication between the surface and subs problematic, and our maps have not always been as accurate as they are now. However, as our research has continued, our knowledge of the area has improved, our communications infrastructure has grown by leaps and bounds, and I daresay, some of us are even getting better at flying these subs! I am proud to say that the circumnavigation went smoothly and we were able to fill in some missing areas in our maps of the herms!

Exploring the herms at 40 feet.

Improving our maps also means raising more questions; such is the nature of exploration, and this dive was no exception. Although many of the morphological trends that I observed were similar to those I have noticed before (adding strength to some of our hypotheses), new subtleties leapt into view. Why, for example, do many of the microbialites along the bottom of the mounds look roughed-up, slightly broken, whitish, and all together kind of crummy? Does it have to do with fluctuating sediment levels at the bases of the mounds? Perhaps. That leads me to questions of how precisely sediment is transported around the mounds: what is the source of the sediment? How often do large sediment flows come down from the surrounding walls? Are the microbialites buried and exposed regularly or does it happen on a timescale of decades or centuries!? For each answer there are new questions, and for each new question there are a handful of associated questions.

Returning to the surface to see a smiling Susan Winnitoy, guiding me back to the barge.

The abundance of new questions is thrilling, and is what keeps bringing us back here. I often find myself chatting with people who are surprised that we haven’t uncovered all of the details of microbialite formation, development, and growth – after all, we have been studying Pavilion Lake for a number of years. Yet that is the appeal of studying microbialites! Microbialite mounds are subject to nearly countless variables – biological, chemical, and physical processes that change through time. Untangling each of those influences is a process – a process that is being helped along by the phenomenal amount of data that we are collecting with the DeepWorker subs, with the GAVIA AUVs, and with our team of SCUBA divers. So, do we understand everything about microbialite formation yet? Nope. Not by far. But with dives like my magical one through the herms, we are getting ever closer! The microbialites of Pavilion Lake have a story to tell, and through our exploration we are listening to the telling.

Ahhhh, Hawaii. The Big Island. Palm trees, tropical ocean, coconuts, yummy coffee – you can’t beat a tropical field destination! Of course, when Allyson and I arrived at the site, this is what we saw…

ISRU Base Camp

Where are all the beaches and palm trees! Can you guess where we are on the Big Island? I’ll give you a few hints. It is quite chilly. We are quite close to the stars. How about this one: we are on the tallest mountain in the world if you measure from the seafloor! If you guessed Mauna Kea, you are correct!

The ISRU field site sits in a crater at about 9000 feet above sea level on the slopes of the extinct volcano Mauna Kea. The site was chosen because of the cold, dusty conditions and the presence of volcanics that are similar in many ways to what exists on the Moon. Working at a high elevation and on the slopes of a mountain can be pretty tough – plenty of wind, occasional dust storms, lots of fog, and the threat of altitude sickness or overexertion. In truth, however, it is also a beautiful place to work. Mauna Kea offers lovely views, interesting volcanic rocks, and the thrill of spending time on such a large and powerful mountain. In fact, Mauna Kea is considered a very spiritually powerful place to the native Hawaiians – you can check out a brief introduction to that history here: http://www.imiloahawaii.org/59/maunakea.

Hawaii... a fine place to do research in February! (Photo: Bekah Shepard)

Base camp is a small tent city. We have a mess tent (yum – lunch!), a medical tent, an administration tent, tents for the scientists, tents for the engineers, and tents that function as garages for the instruments and robotics that are being tested. Allyson and I settled into one of the science tents, but didn’t stay inside too long! Right away, we set about following the various science and engineering teams in their testing activities. Details about what we found to come!

Aloha! That’s right – PLRP is visiting Hawaii! To be more specific, Allyson and myself have journeyed to the Big Island to take part in another exploration analogue test – the In-Situ Resource Utilization (ISRU) Test. ISRU is just a fancy way of saying “using the resources that are in place”, but in this case, we mean resources that are “in place” on the Moon or Mars. Some of the major goals of planetary exploration are sample return (bringing samples from other planets to Earth) and human exploration. Both of these ventures will require lots of fuel, and in the case of human exploration, plenty of oxygen and water. To send enough of these resources to the Moon or another planet would be incredibly expensive, and might even take several trips! Therefore, learning to use resources “in place” to generate fuel, oxygen, and water will be a great help to planetary exploration!

“But what are you Pavilion Lake researchers doing at an ISRU field test?” I hear you cry. It is true that our main focus at Pavilion Lake is the scientific exploration of the lake and its microbialites. However, as our project has grown and the exploration has become more complicated (submersibles, AUV’s, complicated communications, LOTS of people working to support the science) we realized that it can sometimes be challenging to keep the science as the top priority! In our struggles to do science as effectively and successfully as we can, we realized that developing metrics (tools for evaluating how successful we are at doing research) was surprisingly helpful!

Our tent at ISRU-Hawaii. Yes, this really is Hawaii.

We have since gone on to collaborate with folks developing the next generation Lunar Rover, and have applied our metrics to their Desert RATs analogue test site in Arizona. (Check out the NASA analogue site for more information about RATs: http://www.nasa.gov/exploration/analogs/). That collaboration has continued, and when the opportunity arose to test our metrics in yet another analogue setting, we jumped at the chance! Why? The balance between science, engineering, and operations in different in each of these analogue field tests, and that difference helps us to hone our metrics. We are gaining a better and better understanding of how science functions in each of these types of analogues, and that helps us all to become better exploration scientists.

Stay tuned for next time when Allyson and Bekah say “Hey! This is Hawaii! Where are all the beaches and palm trees!?!

If you want to make a bunch of Pavilion scientists excited, just mention “the herms”. I just did my second submersible flight through the herms and it was spectacular! Let me give you a little background, so that you can understand why the flight was such a treat:

A bioherm is a mound constructed by biological organisms. A classic example is a patch reef: a decimeter to meter scale mound that is built by corals, sponges, and other reef animals. You may not think of a mound of organisms as being very sturdy, but just as your body is capable of making hard bones, other organisms such as corals also make hard skeletons. When those skeletons start to pile up, you get a bioherm – a biological mound!

So, what in the world does this have to do with microbialites. Remember that microbialites are “organosedimentary structures”, meaning they are built up of minerals that are influenced by organisms. “Whoa!” I hear you cry, “Does that mean that a microbialite is a bioherm? Well, a single microbialite is not usually defined as a bioherm, but if you pile up enough microbialites, you do end up with a mound that is constructed by organisms! By that definition there are some places in Pavilion Lake where we observe large piles of microbialites that can be defined of bioherms.

Thinking about microbialite bioherms is something that some of us geologists do quite frequently. Long before the organisms that build coral reefs evolved, big bioherms and reef structures still existed. Rather than being built by corals, sponges, or even shells, the ancient bioherms and reefs were built out of microbialites! Can you imagine SCUBA diving or piloting a submersible around ancient microbialite bioherms and reefs! Boy, I wish I had a time machine. Since I don’t have a time machine, I do the next best thing. Can you guess what that is? Yup, I come here and study the microbialites in Pavilion Lake. The details we learn about the microbialites in Pavilion Lake will help us to understand the fossil record of ancient microbialite reefs. That will help us to understand how life evolved on early Earth! Crazy cool stuff!

Ok, back to the Pavilion Lake herms. Here is where we are going to get really confusing! The “herms” are not actually bioherms, hence the lack of the “bio”. The herms are an area of sediment mounds at the southern end of the central basin of the lake. Now I know you are screaming, “but if they aren’t bioherms, which are so cool, why are you crazy scientists so excited about them!” It turns out that even though the herms are just sediment mounds, they are covered by some of the most interesting microbialites in the lake. There are a lot of different microbialite morphologies crammed into a very small space. If you start at the bottom of any given herm, you can often see several distinct morphotypes just by looking up two meters of slope. Likewise, if you move around a herm several meters, you often can see changes in morphotype or surface texture. Those are rapid changes! I’m sure you are asking yourself why the microbialites would be changing that rapidly, and that is one of our big research questions this year! It may be that the mounds are a place of significant environmental variability. In other words, there may be interesting water flow patterns, light conditions, variations in sedimentation, etc. that are unique to the herms. Any of these variables may be influencing the morphology of the microbialites! In short, the herms are a really complicated place, and if you haven’t figured it out yet, the scientists as Pavilion Lake love to study really complicated and interested places!

The day before submersible operations is always rife with anticipation. Our whole team has been working all year to prepare for this mission, so now that we are so close to beginning, it can feel a bit torturous to wait one more day! However, there is lots of work and science to fill today. I spent some of my time today doing my first scuba dives of the field season. To make sure that everyone is safe, we do scuba checkout dives to practice our skills. After completing those, I headed off with a small team to the south basin of Pavilion Lake. We piled into a zodiac (a small, fast, inflatable boat) with our gear, and enjoyed the 10 minute ride south. Alex and Bernard jumped off, and swam over to place some sensors in one of the springs that we have discovered. Mike and I split off to investigate and collect samples of some of the microbial mats that inhabit the shallow waters of the lake.

Bekah preparing for a dive at Pavilion Lake

The mats are exciting for me because I am interested in the way some of the bacterial cells (specifically Cyanobacteria) move. The movement patterns of these single celled organisms can create complex shapes, or morphologies visible to the naked eye. Microbialites are “organosedimentary structures”, which just means that they are structures built out of microbial mats and minerals or sediments. The soft mats that I am studying are building complex structures, but they are not involving lots of minerals and sediments (they aren’t actually forming microbialites, so you might wonder about my interest). However, because the mats form complex morphologies, many of the bacterial behaviors that we observe in the soft mats will help us understand the formation and morphogenesis of other microbialites.

Studying these soft microbial mats involves lots of photographic documentation, as well as collecting samples for studying in the lab. We can actually grow these mats in the lab, and watch how the movement patterns work to build complex shapes. I work underwater with a pair of tweezers and carefully collect small pieces of mat into small plastic tubes. I carefully transport them back to the lab on shore, where we can begin our experiments. It doesn’t look very exciting underwater because I spend lots of time in the same place, but I actually really enjoy it! The mats are fascinating, and working underwater is very relaxing. Submersibles are fun, but sometimes it is nice to get your face right up close to what you are studying. They are both great ways to do science!